The present disclosure generally relates to piezoelectric ceramic materials, more particularly to lead-free piezoelectric ceramic materials based on binary and ternary compositions containing bismuth magnesium titanate or bismuth calcium titanate, together with bismuth potassium titanate-bismuth sodium titanate.
Piezoelectric ceramic materials (also referred to as piezoelectric ceramics or piezoceramics) have been widely used in applications such as actuators, transducers, resonators, sensors, and random access memories. Among those piezoelectric ceramics, lead zirconate titanate (PZT), and its related solid solutions are the most widely used due to their excellent piezoelectric properties and the ease with which modifications by doping can be made during manufacturing. However, there are drawbacks to using PZT which limit its desirability in many applications. One concern is its possible environmental effects due to the toxicity of highly volatile PbO which can evolve from PZT during fabrication. Another drawback of PZT piezoceramics is the strong fatigue behavior associated with PZT. Fatigue is a phenomenon in which a piezoelectric material loses its switchable polarization and electromechanical strain during electrical cyclic loading.